The proposed developmental psychopathology study examines the development of anhedonia during adolescence. Anhedonia, or difficulty experiencing pleasure in anticipation of or response to rewarding stimuli, is a coherent dimension within positive valence systems, has putative neural correlates in frontostriatal circuitry, and is relevant to several forms of serious psychopathology that emerge during adolescence. Anhedonia, a serious symptom, is likely to emerge during adolescence, and we propose that the development of anhedonia could precede the development of affective and schizophrenia-spectrum psychopathology. Specifically, the study examines developmental changes in subjective, neural, and behavioral aspects of anhedonia in 130 adolescents, age 13-17, who are either typically developing or have a first-degree relative with a history of depression, bipolar disorder, or schizophrenia-spectrum disorder. With the goal of understanding the development of anhedonia, the proposed study's aims include investigating (1) differences in anhedonia between high-risk and low-risk adolescents; (2) the development of anhedonia across adolescence; and (3) associations between anhedonia and depression, mania, and psychosis both cross-sectionally and longitudinally. Participants will complete 3 laboratory visits at annual intervals and 2 internet-based assessments, scheduled every 6 months between lab visits. Laboratory visits include self- and parent-report of anhedonia, psychopathology, and functioning; functional magnetic resonance imaging (fMRI) of frontostriatal function in response to monetary and social rewards; and behavioral tasks assessing reward motivation and reward learning. We will use longitudinal growth modeling to test our hypotheses. This study promises to advance mental health research by elucidating the development and pathophysiology of anhedonia, a dimension of psychopathology that occurs across disorders. Resulting understanding can inform the design of innovative, developmentally targeted prevention approaches.